Many electronic devices include energy storage systems and Universal Serial Bus (USB) adapters. In such an electronic device, the energy storage system is typically a rechargeable battery. The USB adapter enables the electronic device to be connected to a USB port of a USB charger via a USB cable. When the electronic device is plugged into the USB port of the USB charger, the rechargeable battery can be charged by a charging current that is output from the USB charger.
In one example, a charger is matched to a particular device having a rechargeable battery. When the charger is connected to the device, power transfer is optimal such that the battery charges in the shortest amount of time. However, if the charger is connected to another device that is not matched to the charger, then the power transfer may be less than optimal such that battery charge times are extended. A more robust solution is desired.